Rotatable vaned element



Seph 28g 1954v H. L. MnscH 2,690,132

ROTATABLE VANED ELEMENT Filed July so, 1951 3mm HERsg/Pr L. /u/scH m7ag$m MMM.,-

Patented Sept. 28, 1954 UNITED STATES OFFICE 2,690,132 ROTATABLE VANED ELEMENT Herbert L. Misch, Roy Packard Motor Car Company, corporation of Michigan al Oak, Mich., assigner to Detroit, Mich., a

2 Claims.

This invention relates to fluid coupling means and more particularly to a varied element of a torque converter or the like and to a method by which the element is formed.

As a preferred example of this invention, reference is made herein to a hydraulic torque converter for the transmission of power from an engine to a load, and as normally constituted, such a converter in-cludes at least three vaned elements which. are so formed that the uid operated upon by the elements travels in a closed path. rihis path is helical since the fluid is driven to rotate in the direction of the movement of the elements as well as across them. The vanes on the elements must therefore be formed to take advantage of the energy of the fluid movement, and this requirement necessitates the use of vanes having rather complex forms and cross-sections.

The conventional method of forming vaned .torque converter elements is to cast them simultaneously with an outer shell and an inner core member, said shell and core member being continuous and serving to make a rigid unified structure with the vanes. Due to the complex structure of the vanes, this is a diflicult casting operation, it being almost impossible to cast the vanes with the smooth surfaces required for eiiicient operation. And because of the complexity of the shape of the casting, the problem of cleaning out the imperfections formed during the casting operation, is rendered more difcult.

The principal object of this invention is, therefore, to produce an improved method and means for forming the vaned element of a torque converter or the like, the element having smooth surfaces on the vanes as Well as on the shell and core.

Another object of this invention is to provide an improved method of casting a vaned element of a torque converter wherein the vanes are formed separately and then united to the shell and inner shroud of the element.

A. more specific object of this invention is to provide a method of forming a vaned element of a torque converter which comprises forming the vanes separately as hollow units, investing the vanes in a molding core, and casting the outer shell and inner shroud around the molding core, the cast material thus forming with the vanes a complete unit. The core material into which the vanes are invested may then be removed by any suitable method.

It is to be understood that the invention here disclosed is not to be limited in its application Cil .to the details of construction and arrangement of parts shown in the drawings since the invention is capable of other embodiments and or" being practiced or carried out in various ways. Also it is to be understood that the phraseology or terminology employed herein is used for the purpose of description only and not by way of limitation.

The preferred embodiment of the invention, however, is shown in the drawings, wherein:

Figure l is a fragmentary front elevation of a mold for a vaned element of a torque converter showing the completed casting including a portion of the core in which the vanes are initially invested;

Figure 2 is a section through the vaned element taken on line 2-2 of Figure 1;

Figure 3 shows one of the vanes prior to its assembly in the molding core;

Figure 4 is a view of the vane of Figure 3 taken in the direction of the arrows 4 4 in Figure 3; and

Figure 5 is a front elevation of a completed casting made in accordance with this invention.

Referring now to the drawings for a more de-y tailed description of the invention, and particularly to Figures 3 and 4- there is disclosed a vane Il) having a blunt, rounded trailing edge l! and a sharp, iiat leading edge l2, the plane surface of the leading edge being turned or twisted relative to the surface of the trailing edge in the manner shown. The portion of the vane adjacent trailing edge il is hollow and this space or aperture i3 extends across the entire vane. The particular shape of the leading and trailing edges of the vane is determined by the characteristics desired in the converter, and hence the shape may be varied without departing from the scope of this invention.

As shown in Fig. 4, an outer surface it of the vane has a contour which coincides with the interior of the enclosing housing or shell that is adapted to enclose a plurality of these vanes Hl. The inner surface i5, is also formed to the contour of the inner shroud portion l1 of the completed element.

Referring now to Figs. 1, 2, and 5, it will be seen that the converter element is made up of a plurality of the vanes I0 spa-ced around the inner periphery of the outer housing I6 of the element, with the inner shroud or ring l1, serving to bridge the inner surfaces l5 of the vanes and thereby coni-lne the movement of the fluid operated upon by the converter here shown, to a circular path.

It has been found in commercial operations that, if the converter element shown in Figs. l and 2 is made as a single unit by a casting process, it is difficult to insure the production of smooth surfaces on the variesl I@ and also on the fluid-contacting surfaces i8 and I9 of the shell and inner shroud, respectively. The casting of such elements results in the formation of a fiash at the leading edge of each vane, thereby producing an irregularity in the contour of the vane and any irregularities found on these surfaces must, because of the complexity of the structure, be removed by a manual grinding operation which is expensive and time-consuming. Even when expertly done, the manual grinding operation is not always entirely satisfactory because it is quite diicult to insert the cleaning tool into certain portions of the curved space between the vanes to reach any irregularities on such surfaces.

The present invention obviates this difficulty by forming vanes lil as individually die cast elements and the openings I3 can be formed in this casting operation. The individual vanes may then be readily cleaned by a tumbling operation or by a hand flash-trimming operation due to the accessibility of all surfaces of the vanes. After a number of the separate vanes have been cleaned, they may be assembled in a circular fixture (not shown) so as a predetermined pattern in the positions they will occupy in the finished torque converter element. In one form the fixture may be designed to have a surface corresponding to the inner surface I8 of shell I5 and another surface corresponding to surface I9 of inner shroud il. The fixture is adapted to close off the ends of the opening I3 in each vane while leaving an opening to each of the spaces between the several assembled vanes. Plaster, or some other temporarily hardenable core material is then poured into this space between the vanes, thereby investing the vanes in a solid core which is used in the subsequent molding operation. The inner and outer surfaces Id and I of the vanes as well as the openings or apertures I3 are set up in the fixture so as to be preserved free from contact with the core material and yet are iixedly but temporarily bonded together by the core in preparation for the nal casting operation.

The fixture is removed after the plaster has hardened, and the core with the vanes invested therein is then placed in a previously prepared mold which corresponds in form, to the outer shell IE and inner shroud I1. When the molten metal is poured into the mold, it forms the outer shell I6 and inner shroud I'I, and it is also poured so that it flows around surfaces I4 and I5 into openings I3 to form posts 29 which pass through the openings I3 in the vanes and are integral with outer shell I6 and inner core I'I. nasmuch as the openings I3 are elongated and follow in general the cross section of each of the vanes I, the posts 2G have a similar form and because of the elongated cross section thereof, prevent turning of the vanes I in the completed element.

It will be noted that openings I3 are of such form as to leave a substantially uniform wall thickness for each vane. This simplifies the casting operation in that difculties usually encountered in casting articles of varying thickness are avoided. After the cast material of shell I and inner shroud I1 has been poured and cooled,

the plaster core may be removed by any suitable to be spaced apart in method such as mechanically crushing it and blowing or Washing it out. The torque converter element is then ready for its final machining operations to condition it for ready assembly with the remaining elements of the converter. Very little, if any, cleaning of the surfaces I8 and I9 is necessary, and, none at all is required on the exposed surfaces of vane IG at this time. Furthermore, the junction between the vanes and inner shroud and outer shell may be made as a sharp corner, but preferably it is curved to eliminate eddies in the flow of fluid through the converter.

Although the molding core material has been described above as a plaster, it may be any other suitable material which will hold its shape at the temperatures and pressures developed in the casting operation and yet will Ibe readily removable after the casting operation is completed.

It is desirable to use a material for shell I6 and inner shroud I'I which will shrink slightly upon hardening in its position surrounding the surfaces I4 and I5 of the vanes, thereby producing a snug t whereby to eliminate all possibility of the assembly rattling when the element is in use. This desired shrinkage is inherent in the conventional aluminum alloys.

inasmuch as the element is to be mounted to rotate with a shaft, the areas of the shell i6, which are to be secured to the shaft by which the element is driven or which the element is to drive, and the clearance areas between adjacent elements, may be machined after the cast element is removed from the mold.

It is understood that various forms of the invention other than those described above may be used without departing from the spirit or scope of the invention.

I claim:

l. A rotatable vaned element for a hydraulic torque converter or the like, said element comprising a plurality of individual vanes disposed about the axis of rotation of the element in circumferentially spaced apart relation, each vane having an inner end and an outer end and having a somewhat thickened trailing edge therebetween and tapering to a thin leading edge, the inner ring having an outer surface relatively adjacent the axis of rotation of the element and engaging the inner end of each vane, an outer ring having an inner surface relatively remote to the axis of rotation of the element and engaging the outer end of each vane, said surfaces being of correspondingly convex curvature about the axis of rotation of the element, each of said va-nes having a radially extending outwardly flared aperture therethrough extending from the inner to the outer end of the same, and a post formed integrally with the rings and completely filling the flared apertures of the respective vanes and cast from the common material of the rings that shrinks upon hardening whereby the varies are securely locked in place between the rings in said element.

2. A, rotatable varied element` for a hydraulic torque converter or the like, said element comprising a plurality of individual vanes disposed about the axis of rotation of the element in circumferentially spaced apart relation, each vane having an inner end and an outer end and having a somewhat thickened trailing edge therebetween and tapering to a thin leading edge, an inner ring having an outer surface relatively adjacent the axis of rotation of the element and engaging the inner end. of. each vane, an outer ring having an inner surface relatively remote Number to the axis of rotation of the element and en- 1,966,104 gaging the outer end of each vane, said surfaces 1,996,229 being of correspondingly arcuate curvature 2,040,640 viewed from the axis of rotation of the element, 5 2,294,837 each of said vanes having a radially extending 2,351,517 outwardly ared aperture therethrough extend- 2,478,306 ing from the inner to the outer end of the same, 2,503,025 and a post formed integrally with the rings and 2,597,510 completely filling the ared apertures of the re- 10 2,598,367 spective vanes and cast from the common material of the rings that shrinks upon hardening T whereby the vanes are securely locked in place Number between the rings in said element. 395,885

15 References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 853,334 Backstrom May 14, 1907 20 Name Date Noack July 10, 1934 Benjamin Apr. 2, 1935 Bedford et al. May 12, 1936 Dodge Sept. 1, 1942 Jandasek June 13, 1944 Orr Aug. 9, 1949i Bolender Apr. 4, 1950 McBride May 20, 1952 Fiser May 27, 1952 FOREIGN PATENTS Country Date France Apr. 17, 1944 

